Anelastic and viscoelastic behaviour of amorphous Zr65Cu17.5Ni10Al7.5 in the range of the glass transition

Reversible (anelasticity) and the irreversible (viscosity) relaxations in the amorphous alloy Zr65Cu17.5Ni10Al7.5 have been investigated by means of creep and mechanic after-effect measurements of the shear strain, which were performed in an inverted torsion pendulum. For the evaluation of the measurements a new relaxation model is proposed which takes into account that in the range of the glass-transition temperature Tg the local atomic arrangement is steadely changing. By introducing a finite mean life time τl of local structure units we are able to trace the origin of the anelasticity and the viscosity to the same atomic relaxation processes. The temperature dependence of the viscosity η measured between 560 K and 668 K shows a jump in the activation energy at Tg = 606 K from 2.1 eV below Tg to 5.6 eV above Tg. (orig.)